Volume-control apparatus



May 11 1926.

D. B. PERRY VOLUME CONTROL APPARATUS Filed Sept. I 16 1925 aynet Rgllgt- I In terrapter INVENTOR. flRBeI r BY J v ATTORNEY Patented May 11,1926.

UNITED STATES PATENT OFFICE.

' nomlm) 1a. PERRY, or Yonimas, New Yong, Assign-on 'ro mnnrcau lrnnlirnonn AND rnnnemn commmr, A coaromrron or NEW YORK.

vommrrconrnor. arrnm'rus.

- Application ma September 16, 1925. Serial No. 56,768.

This invention relates 'to arrangements for controlling the volume of energy transmitted over a signal transmitting-circuit, and more particularly to arrangements for effecting a remote control of the volume.

Where programs are to be transmitted either by wire or radio, particularly where a program consists of musical numbers, the range of volume variation which may be transmitted is limited. The volume must not fall below a minimum level because of noise on the circuit, and it may not exceed a maximum level for the reason thatit might overload vacuum tube apparatus.

such as repeaters, included in the circuit. If the range of variation of the volume of .the signal isgreater than that for'which' the medium is suitable, it has been proposed to regulate the volume at the transmitting end by means of a potentiometer or the like, to

bring it within the volume range of the circuit and to make a-compensatory adjustment of a similar potentiometer atthe receiving end of the system in order to bring the volume as received back to normal. By such an arrangement the overall gain ofthe system may be maintainedconstant and yet the volume actually transmitted may be varied to bring it within the limits of the system .without affecting the range of volume received. a

The purpose of the present invention is to provide an arrangement whereby when the transmitting potentiometer is adjusted, signals may be transmitted to the receiving end to cause a compensating adjustment of the receiving potentiometer. Specifically, the

invention comprises an arrangement by which the adjustment of the controlling potentiometer is made one ste at a time. A signal is transmitted for eac step,-and produces a similar step-by-step adjustment of the distant potentiometer. Preferably, the signal for each step will be the same.

The invention may now be more -fully understood from the following description when read in connection with the accompanying drawing, Figure 1 of which is a circuit diagram showing the preferred form of the invention, Figs. 2 and 3 of which are v the views showing details'of the switch for controlling the tentiometer, in conventional form, and

' in Figs. 4 and'5, respectively.

igs. 4 and 5 of which are curves showing the form of the signal transmitted to control the receiving potentiometer. Y

Referring to Fig. 1, the sending control arrangement is shown on the left half of the diagram, and the receiving. arrangement, on the right half of the diagram, The controlling potentiometer P is 'located at the transmitting station, and determines the gain of the amplifier A. A similar otentiometer P is arranged at the receiving station of the line L, and likewise controls the $6 gain of the amplifier A. The circuit is so arranged that when the potentiometer P is ad usted to increase the gain the potentiometer/P is adjusted to decrease the gain, and

vice versa. A- telegraph or signal line L is provided, and the circuit is} so organized that a signal is s'ent over t e line'L" every time the control potentiometer P is changed one step.

reversals are sent over the line L. A sig nal for stepping the control potentiometer p consists of steady battery for a time equivalent to several cycles. To increase the volume by one step, a steady marking signal is sent out, and to decrease the vol: ume by one step, a steady spacing signal is used. These signals are shown graphically The potentiometer control for the potentiometer P consists of a switch S, shown somewhat in'detail in Fig. 2. The switch consists of two arms, each wiping over an arc-shaped busbar and over a plurality of individual contacts. The upper arm of the switch connects the upper busbar to any one of a plurality of contacts to determine the setting of the potentiometer. The lower arm connects the lower busbar independently to each of a pair of contacts to determine the stepping. signal to be sent to the distant station. As theswitch S must be held in position after being moved one step until the signal is transmitted to the distant sta: tion, it, is provided with a notched disk 10, adapted to be locked by the armature 11 of the release control magnet 12 during the time that a signal is sent.

The switch S controlling the potentiometer P is similar to. the switch S, except that the lower arm and corresponding con- Under normal conditions, steady dots or 76? tacts are omitted. switch-is step mission of dot signals, but when a long automatically by a tdothed disk 11 under closed circuit impulse is received, the slow the control of stepping magnets 12 and 13. release relay 16 will permit its armature At the transmitting station the lower conto drop back for an instant, thereby causing tacts are wired, as shown, so thatnormally he rel y 18 o become energized and lo ked one of the relays X, Y and Z is always up through'the break contact of the step- V winding of the up relay UR to battefiy.

magnet to lock t e switch S and prevent operated, depending upon the position of the ping magnet 13. At the same time, the relay lever arm. The relay Y is shown operated 18 closes a circuit through the stepping in the diagram. The up and down relays magnet 13 and the release magnet 20. The

UR and DB are normally released, so that magnetv20 lifts the pawl of the armature ot the interrupter contact 14 shown in the lower the stepping magnet 12 from the toothed left-hand corner interrupts the telegraph cirdisk, thereby enabling the magnet 13,

cuit 'L extending dots or reversals to the through its pawl, to shift the disk one step receiving control arrangement. The armain a clockwise direction. The controlling ture of the receiving relay RR will vibrate armature S is thus moved one step in a, di-

in response to thesesignals, holding operated rection to reduce the gain of the amplifierthe slow release relays 15 and 16.

Further details of the invention will be clear from a description of the operation, volume control lever at the transmitting which is as follows: station is moved to reduce the gain. Assum- Assume that the control levers 17 and 18 ing, as before, that the lever isin the posiv are in the positions shown by the arrows in tion indicated by the arrows, and that the the diagram of Fig. 1, wherethe busbars Y relay is held operated, now, if the lever and contacts are shown extended horizonis moved to the right so as to decrease the tally .instead of *bei'ng'shown in their normal gain, one stop, a circuit is closed through condition. ,In this diagram, it is also asthe seventh contact of the lower row to sumed that the brushes making contact beenergize the relay Z. At the same time, a

tween each busbar and its associated indicircuit is closed from the grounded busbar 1 vidual contacts are moved both in, the same and the seventh contact in the second row.

direction. When the volume'control lever and thence over the right-hand armature of is moved in the direction which increases the relay Y, which is slow to release, and volume, that is, to the left, the contacts on through the winding of the down relay DR the lower busbar will move one step tothe to battery. The down relay DR operates left. Relay X will now be operated over and remains operated for a short time after a circuit from the lower grounded busbar the relay'Y releases. At its left contact, it to the fifth contact from the left in the holds the release control magnet operated lower row and through the winding of the to lock the switch in its adjusted position, relay); to battery. At the same time, and and at its right hand contact, it opens the before relay Y releases, (relay Y being slow circuit of the line L so that an 0 en circuit to release), a circuit is closed from the impulse of .longer than usual uration is groundedbusbar to the fifth contact in; the transmitted. As soon as the relay DR re-. second row, and thence over the left-Hand leases, the open circuit impulse ceases and frgnt contact ofthe armature of relay Y and the dots are again transmitted. At the The same time, the release control magnet is right-hand contact of the relay U closes released, and the operator is free to move a circuit which 0 crates the release control the control arm another step.

At the receiving end, the receiving further motion of the volume control lever RR is released for several cycles, al until the signal has been sent. The leftthe slow relay 15 to release its armature relay hand contact of the up relay UR shortand complete the momentary circuit-through circuits the interrupter contact 14, closing the windin-gof the relay This relay is th lo p and sending a closed circuit signal locked up over the break contacts of the Isteady si as indicated in Fig. 4. The up relay UR, step ing magnet 12. Relay 17 at its leftbeing 'S in r l W ll r lease sho tly han contact; completes a circuit for the after the relay Y releases, whereupon the stepping magnet 12 and the release magnet will cease and the dots ll be 19. The latter lifts the pawl of the arma continue The release control magnet is .ture of the stepping magnet 13 to free the new deenergized so that the switch may be disk 11, so that the stepping magnet 12 can given an additionalstep, if desired.

step the disk in a counter-clockwise direc- At the receiving end, when this closed tion one step. This shifts the arm of the RR will be held operated for a longer period of the potentiometer.

1 than occurs during the normal transmission.

'of dots: The slow release relays 15 and 16 ciples herein disclosed may be embodied in It will be obvious that the general prinare both held energized during the transmany other organizations widely difi'erent owing The circuit operation is similar when the I25 circuit signal is received, the receiving relay switch S to the left, and increases the sin 'tiometer at the transmittin from' those illustrated, 'without departing from the spirit of the invention, as defined .in the following claims.

means at the distant station responsive to the closed circuit dash to produce a correspond- "ng adjustment of thepotentiometer at that station.

2. In a volume control system, a potentiometer at the transmitting station, and a potentiometer'at the receiving station, a controlling switch for adjusting one of said p0- tentiometers, means to transmit dots to the distant station when no adjustment is being made, and means to transmit a closed circuit dash to the distant station when an adjust- .ment is made in one direction, means to transmit an/ open circuit dash in response to a circuit adjustment in *the opposite direction, and means at the'distant station responsiv'e to the closed circuit dash to adjust the potentiometer thereat in one direction and responsive to the oppn circuit daslrto adjust the potentiometer t ereat in the opposite direction. r

3. In a volume control system, a potentiometer at the transmitting station, and a potentiometer at the receiving station, a controlling switch for adjusting one of said po tentiometers, means to transmit dots to.

,the distant station when no adjustment is being made, and means. to transmit a closed circuit dash to the distant station when an adjustment is made in one direction, means at the dist-ant station responsive to the closed circuit dash to 'pro-- duce a correspondingadjustment of the potentiometer at that station, and means to hold the otentiometer at the first station in adj uste position until the signal is transmitted.

4. In 'a' volume control system, "a potenpotentiometer at the receiving station, a contentiometers, means to transmit dots to the 'tiometer at the transmitting station, and a distant station when no adjustment is being made, and means to transmit a closed cir- 'cuit dash'to the distant station when an adjustment is made in one direction, means to transmit an open circuit dash in response to a circuit adjustment in the opposite direction, means atthe distant station responsive to the closed circuit'dash to adjust the potentiometer thereat in one direction and re- "sponsive to the open circuit dash to adjust the potentiometer thereat in the opposite direction, and means to hold the'potentiometer at the first station in' adjusted position until the signal is transmitted:

In testimony whereof, I have signed my f DONALD PERRY.

10 name to this specification this 14th day of September, 1925. a j 1 v 

